A myocardial infarction is the irreversible damage done to a segment of heart muscle by ischemia, where the myocardium is deprived of adequate oxygen and metabolite removal due to an interruption in blood supply. Ischemia is usually due to a sudden thrombotic occluion of a coronary artery, commonly called a heart attack.
If the coronary artery becomes completely occluded and there is poor collateral blood flow to the affected area, a transmural or full-wall thickness infarct can result in which much of the contractile function of the area is lost. Over a period of one to two months, the necrotic tissue heals, leaving a scar. The most extreme example of this is a ventricular aneurysm where all of the muscle fibers in the area are destroyed and replaced by fibrous scar tissue.
Even if the ventricular dysfunction as a result of the infarct is not immediately life-threatening, a common sequela of a transmural myocardial infarction in the left ventricle is heart failure brought about by ventricular remodeling. Heart failure refers to a condition where cardiac output falls below a level adequate to meet the metabolic needs of the body which, if uncompensated, leads to rapid death.
It is believed that preventing heart remodeling can prevent heart failure. Placing patches or substrates over the myocardial infarction is a therapy used to prevent heart remodeling. Such patches or substrates are implanted via highly invasive open chest procedures.
There is a need in the art for a patch or substrate that is deliverable to a myocardial infarction via less invasive methods. There is also a need for a less invasive method of delivering a patch or substrate to a myocardial infarction.